This invention relates generally to a device for draining liquids through an aperture and, more particularly, to a moveable valve member for draining liquids through an aperture and preventing the flow of gases through the same aperture, the device especially employed in systems adapted to ensure that gases are not allowed to enter and collect in an enclosure.
Power plant facilities require large supplies of fuel that are necessary to operate the facility. At such power plant facilities, it is necessary to also have containment structures such as storage tanks or enclosures, typically located underground or below the earth line, to collect and store waste by-products, such as fuel oils, that are generated during operation of the facility. The enclosures collect and contain these waste by-products in order to prevent environmental contamination.
During such normal operations of the facility, the waste by-products that are liquids are sent through a conduit (flow passage) and into the enclosure. Waste gases, unlike waste liquids pass into the flow passage and are vented into the atmosphere, as opposed to being sent to the enclosure.
One of the problems that may be encountered during such operations is the accumulation of waste fuel gases inside the enclosure. It is common practice to prevent such accumulation of gases inside the enclosure by employing the control means to prevent the gases from entering and consequently, filling the enclosure and other enclosures that may be in flow communication with the enclosure. However, should the control means fail for any reason, gas would be permitted to enter the enclosure. This would be an undesirable situation.
Valve mechanisms for separating oil and water have been suggested. Clark et al., U.S. Pat. No. 4,580,592 shows an open vessel separator valve connected to a conduit at the bottom of the tank to drain the water that collects at the bottom of the tank. However, the valve disclosed in this reference is designed to be located at the bottom of the tank and is not adapted for use in a conduit through which liquids can flow to fill the tank. Fetsch et al., U.S. Pat. No. 4,425,933 discloses an oil and water separator for use in a secondary containment structure around a storage tank. The separator includes a float that is fixedly attached (hinged) to an actuator arm and is designed for operation underground and in a moat surrounding the tank. It is noted that these types of separation devices require the separation of fluids that have already been mixed in the tank such that the valves are used to eliminate one of the fluids that has previously accumulated inside the tank without draining the other fluid from the tank. These devices are also designed for use at the discharge or bottom section of the tank.
Therefore, what is needed is a reliable, simple, economic and non-manual device that permits liquids, such as fuel oils, to be drained into the enclosure while preventing the flow of gases into the enclosure. Such a device would be located at the flow entrance of the tank.
The above discussed and other drawbacks and deficiencies are overcome or alleviated by the present invention.
Accordingly, the present invention provides a reliable, simple and economic, device that permits liquids, such as fuel oils, to be drained into the enclosure while preventing the flow of gases, such as hydrocarbon fuels, e.g. natural gas, into the enclosure. The device is positive acting with a minimal number of parts and is not susceptible to the development of defects.
It is preferred that the device includes a valve housing having a chamber for receiving the liquids and the gases and a drain valve means that is in open flow communication with the liquids and gases. The drain valve means includes a valve seat and a float member. The float member is located within the valve housing and arranged to engage the valve seat to open and close an outlet in the valve housing. The float member has a specific gravity less than the specific gravities of liquids and more particularly, liquid fuels, e.g. diesel oil, gasoline, kerosene, etc. In this way, the float member floats off the valve seat when the liquids flow through the valve housing and engages the valve seat when gases are present in the chamber. Thus, the liquids within the chamber pass through the device and enter the enclosure while the gases within the chamber are prevented from entering the enclosure.
It is most preferred that the float member is made of anodized Aluminum, has a hollow interior and is spherically shaped. It is most preferred that the float member has a specific gravity less than approximately about 0.2. Also, the flow rate of the liquids entering into the chamber is of a predetermined flow rate. Preferably, the flow rate, the configuration of the device and the shape, material and size of the float member are optimized with respect to one another to permit the float member to float off the valve seat when liquids are present in the device and more particularly, the chamber. However, the valve housing and the float member could have alternative configurations which can produce the same effect of opening and closing the device and more specifically, permitting the flow of liquids and not gases present in the chamber. The valve seat is a machined surface that can have alternative configurations that match the contour of the float member.